Pilot type controlled electromagnetic valve system

ABSTRACT

The pilot type controlled electromagnetic valve system in accordance with the present invention is opened and closed principally by means of automatic remote control. 
     The controlled valve system comprises a main valve F; a pilot valve G for opening and closing the main valve F by means of the fluid pressure on the primary side; a latching solenoid H for opening and closing the pilot valve G; and a solenoid drive control unit I for driving the solenoid H by supplying a discharge current from a capacitor to the solenoid. A pulse discharge current is supplied to the solenoid H from the capacitor C only when the pilot valve G is opened or closed, and no excitation current is supplied continuously through the coil of the solenoid. As a result, the power source battery can be reduced in size, and therefore virtually no accidents take place in the controlled valve system due to no heat generation in the coil.

BACKGROUND OF THE INVENTION

The present invention relates to a compactly-designed and energy-savingpilot type controlled electromagnetic valve system for use mainly incontrolling water supply.

In recent years, a so-called automatic meter check system utilizing amicroprocessor-controlled water meter has been under development for thewater supply systems in large cities. FIG. 3 shows the construction of atypical automatic meter check system. In FIG. 3, the meter check centerA of the water supply side and the intensive meter check control unit Bof the user side telecommunicate via a telephone line C to remotely andintensively control the reading of the water meter D of each user, aswell as the opening and closing operations of the water supplycontrolled valve system E via the intensive meter check control unit B.

Such a water supply controlled valve system E usually takes the form ofa pilot type controlled electromagnetic valve system as shown in FIG. 4.In FIG. 4, when the coil 1 of a solenoid is excited through remotecontrol to attact a plunger 2 for separating a valve disk 3 from itsvalve seat 4, the water pressure inside the bonnet chamber 5 of the mainvalve F is released successively through a fluid path 6, a pilot valvechamber 7, and a fluid path 8 toward a secondary fluid path 9.Consequently, a diaphragm 11a is pressed upward by the primary fluidpressure P₁ to push the valve disk 11 upward against the force of aspring 10. With the above operation, the primary fluid path 12 iscommunicated with the secondary fluid path 9 to consequently open themain valve F.

When the excitation of the coil 1 is interrupted, the pilot valve 3moves downward to close the fluid path 8. With this operation, the fluidin the primary path is conducted into the bonnet chamber 5 of the mainvalve F successively through a primary pressure path 13, the pilot valvechamber 7, and the fluid path 6, by which the internal pressure of thebonnet chamber 5 is increased by the primary fluid pressure to press thevalve disk 11 downward and consequently close the main valve F.

However, in a controlled electromagnetic valve system having the aboveconstruction, it is necessary to continuously supply a large current toexcite the solenoid coil during the opening or closing operations of themain valve F. Therefore, a power source having a large capacity isnecessary in order to cope with the large power consumption, which alsoincurs the problems of heat generation, etc.

Furthermore, for the integration of a driving power inside thecontrolled valve system, it is difficult to reduce the size of thevalve, due the necessity of having a large-sized power source for theabove reasons, which also results in a significant increase in the sizeof the water supply controlled valve system.

The present invention provides a novel controlled electromagnetic valvesystem for water supply permitting size reduction as well as power orenergy savings, by eliminating the above-mentioned problems accompanyingany conventionally controlled electromagnetic valve system for watersupply, with the problems being: (1) the necessity of a large powercapacity for the opening or closing operations of the valve system,leading to an increase in size of the driving power unit; (2) thedifficulty in reducing the size of the valve system for structuralreasons, etc.

SUMMARY OF THE INVENTION

Generally, the valve in an electromagnetic valve system of the abovetype is not frequently subjected to opening or closing operations forwater supply, but held in an opened or closed condition for a long time.Therefore, the valve is not required to have a rapid operation speed inthe opening or closing operations.

The controlled valve system in accordance with the present invention hasbeen developed in view of the above characteristics of the valve systemduring use. In detail, by employing a latching type solenoid andcharging a capacitor for a certain period to perform valve opening andclosing operations using a discharge current of the capacitor; thedimensional reduction of the entire system, the minimization of powercapacity, and energy savings are obviated.

An object of the present invention is to provide a pilot type controlledelectromagnetic valve system comprising a main valve; a pilot valve forselectively controlling a fluid flow path extending from the main valvethrough the pilot valve to thereby control operation of the main valve,the pilot valve comprising, a plunger means movable between a firstposition whereat it blocks the fluid flow path and a second positionwhereat it does not block the fluid flow path, a spring for biasing theplunger toward the first position, a permanent magnet for generating aflux retaining the plunger at the second position, and coil means forselectively generating magnetic fields to move the plunger from one ofthe positions to the other; and, a drive control circuit for applying afirst or a second excitation current pulse to the coil means, the coilmeans being responsive to the first excitation current pulse for movingthe plunger from the first to the second position against the bias ofthe spring means, and responsive to the second excitation current pulsefor generating a flux offsetting the retaining flux of the permanentmagnet whereby the plunger is moved to said first position by thespring.

The drive control circuit comprises first and second capacitors; abattery; switch means connected to the battery and the first and secondcapacitors, the switch means including means responsive to a firstsignal for connecting the battery to the first capacitor to charge thefirst capacitor and means responsive to a second signal for connectingthe battery to the second capacitor to charge the second capacitor, andfirst and second gating devices, the first gating device being connectedto the first capacitor and the coil means for gating the charge on thefirst capacitor into the coil means as the first excitation currentpulse, the second gating device being connected to the second capacitorand the coil means for gating the charge on the second capacitor intothe coil means as the second excitation current pulse.

Other objects of the invention and its mode of operation will becomeapparent upon consideration of the following description and theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section view of a controlled electromagnetic valvesystem in accordance with the present invention,

FIG. 2 is the circuit diagram of a solenoid drive control unit.

FIG. 3 is a block diagram of a water supply automatic meter check systemto which the pilot type controlled electromagnetic valve system of thepresent invention is applied.

FIG. 3 is a vertically sectioned view of a conventional pilotelectromagnetic valve system.

DETAILED DESCRIPTION OF THE INVENTION

The following describes an embodiment in accordance with the presentinvention based on FIGS. 1 and 2. Note that in, in FIGS. 1 and 2, theparts equivalent to those in FIG. 4 are denoted with the same referencenumbers.

FIG. 1 is a vertically sectioned view of a controlled electromagneticvalve system in accordance with the present invention. The controlledelectromagnetic valve system is composed of a main valve F, a pilotvalve G, a latching solenoid H, and a solenoid drive control unit I.

The main valve F is composed of a valve housing 14, a bonnet 15 providedwith an integrated pilot valve G, and a valve disk 11. The valve housing14 includes a primary fluid path 12, a diaphragm valve seat 16, and asecondary fluid path 9. The valve disk 11 is composed of a diaphragm 11aand a disk plate 11b. The valve disk 11 is disposed between the bonnet15 and the valve housing 14 with interposition of a spring 10 to bemounted on the diaphragm seat 16, which can be separable and accessiblewith respect to the diaphragm seat.

The pilot valve G is formed integratedly with the bonnet 15, andcomposed of a valve housing 15a formed with a pilot valve chamber 7 anda valve seat 4 as well as a disk 3. The valve chamber 7 is communicatedwith a bonnet chamber 5 via a fluid path 6, communicated with theprimary fluid path 12 via a fluid path 13, and communicated with thesecondary fluid path 9 via a fluid path 8. By opening and closing thefluid path 8 with the upward and downward movements of the disk 3, thevalve disk 11 of the main valve F is moved upward and downward to openand close the main valve F.

In more detail, a plunger 2 of a solenoid H (described in detailhereinafter) protrudes downward to make the valve disk 3 abut againstthe valve seat 4 by the force of a spring 17 and consequently closes thefluid path 8. With this operation, the water pressure on the primaryside is exerted inward toward the bonnet chamber 5 successively via thefluid path 13, the valve chamber 7, and the fluid path 6. Consequently,the diaphragm valve disk 11 abuts against the valve seat by the pressureof the spring 10 to close the valve. Conversely, when the plunger 2 isattracted upward against the force of the spring 17 to open the fluidpath 8, the water pressure inside the bonnet chamber 5 decreases.Consequently, the diaphragm disk 11 is pressed upward by the waterpressure P₁ on the primary side to open the main valve F.

The monostable latching solenoid H is composed of an excitation coil 1,a plunger 2, a spring 17, a yoke 18, an iron core 19, a permanent magnet20, etc. The tip portion of the plunger 2 is connected to the disk 3 ofthe pilot valve G.

In the monostable latching solenoid H, there is no current through theexcitation coil 1, except during a short period at the activation time.The plunger 2 is held in the retracted position against the force of thespring 17 by the magnetic flux passing through the permanent magnet 20,plunger 2, iron core 19, yoke 18, and permanent magnet 20. Consequently,the disk 3 is separated from the valve seat 4 to open the pilot valve Gand the main valve F.

In order to close the main valve F, an excitation current in a pulsewaveform is generated in the excitation coil 1 from the solenoid drivecontrol unit I (described in detail hereinafter) to generate a magneticflux for offsetting the magnetic flux of the permanent magnet 20. Thegenerated magnetic flux momentarily reduces the magnetic flux throughthe plunger 2, by which the plunger 2, whose holding force is now lost,is pushed downward by the force of the spring 17 to close the pilotvalve G. The plunger 2 is of course held in the downward protrudingposition by the force of the spring 17. The closing operation of thepilot valve G also closes the main valve F as explained hereinbefore.

FIG. 2 shows an example circuit of the solenoid drive control unit I, inwhich the numeral 1 denotes the excitation coil, the numerals 22 and 23denote SCRs, the numerals 22a and 23a denote the SCR gates, the numeral24 denotes the power source battery, the numeral 25 denotes a changeoverswitch, and the numeral 26 denotes a signal input terminal.

When a signal representing of "open valve" is input to the inputterminal 26 from an intensive meter control unit B, etc., the contact25a of the changeover switch 25, which is normally in the open position,is connected to the terminal 25b. When a signal representing of "closevalve" is input to the input terminal 26, the contact 25a is connectedto the contact 25c.

When the "open valve" signal is input to the input terminal 26 toconnect the battery 24 across the terminals S₁ and Sc, firstly thecapacitor C₁ starts to be electrically charged. When the terminalvoltage across the capacitor C₁ is increased to a predetermined valuewith the electric charge and the input voltage to the gate 22a reaches avalue for permitting operation, the SCR 22 conducts a discharge currentfrom the capacitor C₁ through a part of the excitation coil 1 in thedirection indicated by an arrow a. Consequently, the plunger 2 isattracted, to open the pilot valve G and the main valve F.

Conversely, when the "close valve" signal is input to the input terminal26, the battery 24 is connected across the terminals S₂ and Sc to startcharging the capacitor C₂. When the charging of the capacitor C₂ makesthe input voltage of the gate 22b reach a predetermined value, the SCR23 conducts a discharge current from the capacitor C₂ through a part ofthe excitation coil in the direction indicated by an arrow b.Consequently the pilot valve G and main valve F are closed.

The charging periods of the capacitors C₁ and C₂ are individuallyselected to be 30 to 120 seconds, while the conducting period of theSCRs 22 and 23 are individually selected to be 0.1 to 0.2 second. Thecontact 25a of the changeover switch 25 is set back to the open positionby inhibiting the input signal to the input terminal 26 when thedischarging operations of the capacitors C₁ and C₂ are completed.

The power source battery 24 takes the form of a solar battery or alithium battery (1,300 mAH, 6 V). It has been assured that the abovebatteries can provide power for opening and closing the main valve F,where the former can operate semipermanently and the latter can operatefor more than 4 years when used ten times a day.

The controlled valve system in accordance with the present inventionadopts a way of charging the capacitor C in a certain period from thebattery power source 24 and automatically supplying a pulse dischargecurrent to the excitation coil 1 from the capacitor C after completionof the charging operation. Therefore, even a battery power source 24having a comparatively small capacity can provide the impulse excitationcurrent necessary for operating the solenoid. In comparison to a case inwhich a certain excitation current for activating the excitation coil 1is directly supplied from the battery power source, the system of thepresent invention has the advantage of a reduced battery capacity. As aresult, a compact battery can be used, which also leads to a reductionin the size of the controlled electromagnetic valve system.

As mentioned above, the controlled valve system in accordance with thepresent invention can provide superior effects in many applications.

What is claimed is:
 1. A pilot type controlled electromagnetic valvesystem comprising:a main valve; a pilot valve for selectivelycontrolling a fluid flow path extending from said main valve throughsaid pilot valve to thereby control operation of said main valve, saidpilot valve comprising:plunger means movable between a first positionwhereat it blocks said fluid flow path and a second position whereat itdoes not block said fluid flow path, spring means for biasing saidplunger means toward said first position, a permanent magnet forgenerating a flux retaining said plunger means at said second position,and coil means for selectively generating magnetic fields to move saidplunger means from one of said positions to the other; and, a drivecontrol circuit for applying a first or a second excitation currentpulse to said coil means, said coil means being responsive to said firstexcitation current pulse for moving said plunger means from said firstto said second position against the bias of said spring means, andresponsive to said second excitation current pulse for generating a fluxoffsetting said retaining flux of said permanent magnet whereby saidplunger means is moved to said first position by said spring means; saiddrive control circuit comprising:first and second capacitors, a battery,switch means connected to said battery and said first and secondcapacitors, said switch means including means responsive to a firstsignal for connecting said battery to said first capacitor to chargesaid first capacitor and means responsive to a second signal forconnecting said battery to said second capacitor to charge said secondcapacitor, first and second gating devices, said first gating devicebeing connected to said first capacitor and said coil means for gatingthe charge on said first capacitor into said coil means as said firstexcitation current pulse, said second gating device being connected tosaid second capacitor and said coil means for gating the charge on saidsecond capacitor into said coil means as said second excitation currentpulse; said first gating device having a control electrode responsive toa voltage on said first capacitor for gating the charge on said firstcapacitor into said coil for a first interval of time, and, said secondgating device having a control electrode responsive to a voltage on saidsecond capacitor for gating the charge on said second capacitor intosaid coil means for a second interval of time.
 2. An electromagneticvalve system as claimed in claim 1 wherein said first and secondintervals of time are between 0.1 second and 0.2 second.
 3. Anelectromagnetic valve system as claimed in claim 1 wherein said firstand second gating devices are responsive to the voltages on said firstand second capacitors, respectively, attained between 30 seconds and 120second after said switch means connects said battery to said firstcapacitor, or said second capacitor.
 4. An electromagnetic valve systemas claimed in claim 1 wherein said first and second gating devices arefirst and second silicon controlled rectifiers.
 5. An electromagneticvalve system as claimed in claim 1 wherein,said main valve comprises amain valve body having a valve seat, a diaphragm valve disk cooperatingwith said valve seat to selectively control fluid flow through said mainvalve from a primary fluid path to a secondary fluid path, and a bonnetmounted on said main valve body and cooperating with said diaphragmvalve disk to form a bonnet chamber; said pilot valve having a pilotvalve housing fixed to the main valve housing and having a pilot valvechamber therein, a pilot valve seat, and a pilot valve disk carried bysaid plunger means and cooperating with said pilot valve seat; saidfluid flow path comprising a first fluid passage extending from saidsecondary fluid path to said pilot valve chamber through said pilotvalve seat, and a second fluid passage connecting said pilot valvechamber and said bonnet chamber; and a further fluid path connectingsaid pilot valve chamber with said primary fluid path.